Is my traction battery failing?

Yesterday at 153,000 miles my battery acted up again. I did the same repair as last time. Turns out again it was just one module reading a volt low. It was not the same one as last time. I replaced the bad module with one of the extra ones II bought six months ago and now my car is fixed again. The repair took me lestt than 3 hours. I will see how long it will go this time.

 

Here is an update and maybe someone can help. I did the module replacement the other day and the folowing day another module went bad. I did the repair one more time. I did have some problems. When taking the hybrid battery pack apart the modules were swollen and popped apart. I immediatly took out all of modules out and put them in the freezer for an hour and they went back to normal size. I then finnished the module replacement. After driving the car 20 minutes or so I now get an trouble code p3015. I have been reseting it and it keeps coming back. According to the error code charts it means battery block 5 becomes weak. Does anyone know what this means? Any helpfull advise would be very appreciated.

Also in repsonse to the last post. I did take a 3000 mile trip last month up to Indiana, Michigan and the Smokey Mountains. I went through tons of mountains and hills.

 

Do you think the abnormally high internal resistance could be caused by a loose nut on the bus bar? One of the nuts might have been stripped a little and would not tighten as tight as the other ones. Maybe thats the cause. The car is running fine except for the error code tripping the warning lamp.

 

I'm still running with no warning lights. I am now upto 171,000 miles. After the
last repair, I did clean the copper bus that connected module 9 and 10, added a little washer that helped with the stripped thread on the loose nut and, also used a little dielectric grease.

 

Here is my latest update. I just hit 176k miles and the red triangle and amber circle with the exclamtion point showed up. Interesting fact it came on right when I replaced my left rear taillight. The LED on the old one went out. My ObdII Can tester did not show the error code, so I took it into a dealership and they told me it was P3000 - batery control system. Any advise would be appreciated. I can clear it, with my obdIIcan tester, but lights come right back on.

 

Alright, I took the battery apart. The cells were all in good shape. I took all of the copper bus bars out and soaked them in tarnex. I put everything back together. I drove. 10 miles and the triangle and amber warning light came back on. The dealership said bad news you need a new battery and they just dropped the price $1500. I thought since all of the cells tested good, they can't be right. I purchased a used battery ecu and wires from a local prius guy. I tore the battery appart and replaced all of the parts. I then drove 10 miles and the lights came up again. Somehow I thought the error had something to do with the battery fan. I took the fan off and tested it bu hooking it up to an h.o. train set using some alligator clip wires. The fan worked well. I then isntalled the fan back on the car, then jiggled a plastic connector plug and it started running and then turned off. I checked the plug and. Ther were two corroded pins. I snipped the wires and soldered a wire two connect them together. Shazam, It's fixed. It was just one little wire and it had nothing to do with the battery. Just so happens that plug was right near the taillight I repaired the other day. It was probably bad and when I bumped the wires it lost the connection.

 

The plug that was corroded was not the plug that went directly into the battery fan motor. The plug that was corroded was clipped to the silver fan mounting bracket closer to the rear hatch. The bad wire was the black connetion, although I jumped the black and the brown. There were two or three other color connections in the plug that looked good.